Covered stadiums have enjoyed a certain popularity for their controlled environments suitable for sporting and other events regardless of weather conditions. Unfortunately, during periods of fine weather the controlled environment of the covered stadium may detract from the enjoyment that one may derive from enjoying a spectacle in natural ambient conditions. In an effort to satisfy patrons, stadiums covered with retractable roofs have been devised which allow the interior of the stadium to be exposed during favourable weather conditions. One obvious problem with roofs of this type is that they are quite expensive to construct. Further, some dissatisfaction has been found in that some stadiums do not open sufficiently to achieve complete exposure of the interior of the stadium. In one known type of structure, a rectangular roof slides away as a complete unit, while in another type of structure a round roof is opened in the manner of a camera lens shutter. It is obvious that the sliding roof requires additional land for roof storage when open while the shutter roof leaves an overhanging arch.
To meet problems found in these past forms of movable roof structures, U.S. Pat. No. 4,676,033 to Allen and Robbie issued Jun. 30, 1987, comprises a roof having a central arch which separates a pair of ungular (i.e., hoof-like) end segments, one end segment being fixed, the other end segment being movable into nesting relationship with the fixed end segment, and the central arch being movable to nest above the fixed end segment, to expose the interior of the stadium. While the latter structure is an improvement over the previous removable roof covered stadiums, it is not a true dome stadium because the dome appearance is only approximated. By the term "true dome" is meant a continuously curved roof which does not require steps between adjacent segments to allow the roof to open or close.
Further, where the removable roof requires rectilinear movement of the roof structure by means of multiple bogies in two parallel lines, there are problems related to skewing of the roof. In the roof structure of Allen and Robbie it has been noted that the ungular roof segment which moves in a curved linear path creates no problems related to skew as do those portions of the roof which move rectilinearly.
To overcome these problems, it is an object of the present invention to provide a stadium having a repositionable roof of relatively simple construction giving maximum exposure of the interior of the stadium.
It is a further object of the present invention to provide a stadium having a repositionable roof which is a true dome.
Another object of the present invention is to provide a stadium having a repositionable roof, the opening and closing of which creates a visual spectacle for stadiumgoers.
Another object of the present invention is to eliminate the complexity of skew in the movement of a roof segment.